1. Field of the Invention
This invention relates generally to rolling mills producing hot rolled steel rod, and is concerned in particular with an improvement in the equipment used to form and deposit the rod in overlapping rings on a cooling conveyor.
2. Description of the Prior Art
In a typical rod rolling mill, the finished product is directed along a delivery path to a laying head where it is formed into a continuous series of rings. The rings are deposited in an overlapping pattern on a conveyor for continued transport along the delivery path to a reforming station. While on the conveyor, the rings are cooled at a controlled rate in order to achieve predetermined metallurgical properties.
Cooling is achieved by directing a gaseous coolant, typically forced air, upwardly through the overlapping ring pattern from underlying slots or nozzles. The slots or nozzles are configured and prearranged to apply a greater volume of coolant along the sides of the conveyor, where the ring density of the overlapping pattern is relatively high as compared to that at the center of the pattern.
This will achieve optimum results if the ring pattern is maintained centrally on the conveyor. However, experience has shown that different rod diameters have an effect on ring disposition on the conveyor. For example, larger diameter rings tend to lay to one side of the conveyor (to the right when looking from the laying head towards the reforming station). If the ring pattern is allowed to stray from the center of the conveyor, cooling uniformity suffers because the cooling slots or nozzles no longer perform as expected.
Numerous solutions have been proposed for controlling the position of the overlapping ring pattern on the conveyor. These include deflectors for laterally shifting the ring pattern as it is transported along the conveyor (U.S. Pat. No. 5,052,124), and mechanisms for pivotally adjusting the receiving end of the conveyor (U.S. Pat. No. 5,079,937). These attempted solutions have either failed to achieve the desired alignment of the ring pattern on the conveyor, or have caused other problems, for example scratching of the ring surfaces.